Review of Bee Health

MM: A recent Washington State University (WSU) study measured honey bee colony exposure to four neonicotinoid insecticides (clothianidin, dinotefuran, imidacloprid, and thiamethoxam) in urban, rural and agricultural settings. What did the researchers find?

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[JC:] In rural or urban landscapes, they found less than 5 percent of beehives in a two-year period had any detectable residues at all. The authors of the study concluded there is no risk of adverse effect on beehives in rural and urban landscapes, and there was a very low risk in agricultural landscapes. The highest amount found was 3.9 parts per billion in an agricultural landscape. EPA considers 25 parts per billion the cutoff for potential for adverse effects.